Parker, I wouldn't be too concerned with the "sweet spot" as production rates and reserves per well are heavily influenced by the drilling and completion technology applied. Also, there is the Bossier Shale potential that may be more prevalent in Texas.
I believe individual company maps are will promote areas where they have good acreage positions. Eventually you will see excellent production rates all over the "blobs".
Scott, in case you are interested the following is my estimate of Haynesville Core area (square miles) by parish/county from the Chesapeake blob map. It totals slightly more than Chesapeake's 3.5 million acres.
Louisiana
DeSoto 877.3
Red River 388.6
Caddo 661.6
Bossier 419.3
Bienville 202.7
Sabine 259.6
Natchitoches 213.6
Sub-Total 3,022.6
Texas
Harrison 899.0
Panola 664.8
Shelby 635.2
Gregg 109.6
Rusk 231.0
San Augustine 79.2
Sub-Total 2,618.8
The total for both states is 5,641.4 square miles.